The Impact of Engine Design Constraints on Diesel Combustion System Size Scaling

2010 ◽  
Author(s):  
Chang-Wook Lee ◽  
Rolf D. Reitz ◽  
Eric Kurtz
Keyword(s):  
System Size ◽  
Diesel Combustion ◽  
Combustion System ◽  
Design Constraints ◽  
Size Scaling ◽  
Engine Design ◽  
The Impact

scholarly journals Performance Analysis of Preemptive Priority Retrial Queueing System with Disaster under Working Breakdown Services

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 419 ◽  
Author(s):  
Sherif Ammar ◽  
Pakkirisamy Rajadurai
Keyword(s):  
Queueing System ◽  
Cost Optimization ◽  
System Size ◽  
Supplementary Variable ◽  
Preemptive Priority ◽  
Variable Technique ◽  
Retrial Queueing System ◽  
Retrial Queueing ◽  
Busy Server ◽  
The Impact

In this investigation, a novel sort of retrial queueing system with working breakdown services is introduced. Two distinct kinds of customers are considered, which are priority and ordinary customers. The normal busy server may become inadequate due to catastrophes at any time which cause the major server to fail. At a failure moment, the major server is sent to be fixed and the server functions at a lower speed (called the working breakdown period) during the repair period. The probability generating functions (PGF) of the system size is found using the concepts of the supplementary variable technique (SVT). The impact of parameters in system performance measures and cost optimization are examined numerically.

Engine Design Strategy for Boundary Layer Ingesting Propulsion Systems With Multiple Non-Symmetric Engine Inlet Conditions

2013 ◽  
Author(s):  
Jonathan C. Gladin ◽  
Brian K. Kestner ◽  
Jeff S. Schutte ◽  
Dimitri N. Mavris
Keyword(s):  
Boundary Layer ◽  
Design Strategy ◽  
Total Power ◽  
Design Strategies ◽  
Fuel Burn ◽  
Practical Strategy ◽  
Engine Design ◽  
Vehicle Aerodynamics ◽  
Inlet Conditions ◽  
The Impact

Boundary layer ingesting inlets for hybrid wing body aircraft have been investigated at some depth in recent years due to the theoretical potential for fuel burn savings. Such savings derive from the ingestion of a portion of the low momentum wake into the propulsor to reenergize the flow, thus yielding total power savings and reducing required block fuel burn. A potential concern for BLI is that traditional concepts such as “thrust” and “drag” become less clearly defined due to the interaction between the vehicle aerodynamics and the propulsive thrust achieved. One such interaction for the HWB concept is the lateral location of the inlet on the upper surface which determines the effective Reynolds number at the point of ingestion. This is an important factor in determining the amount of power savings achieved by the system, since the boundary layer, displacement, and momentum thicknesses are functions of the local chord length and airfoil shape which are all functions of the lateral location of the engine. This poses a design challenge for engine layouts with more than two engines as at least one or more of the total engines will be operating at a different set of changing inlet conditions throughout the flight envelope. As a result, the engine operating point and propulsive performance will be different between outboard and inboard engines at flight conditions with appreciable boundary layer influence including key flight conditions for engine design: takeoff, top of climb, and cruise. The optimal engine design strategy in terms of performance to address this issue is to design separate engines with similar thrust performance. This strategy has significant challenges such as requiring the manufacturing and certification of two different engines for one vehicle. A more practical strategy is to design a single engine that performs adequately at the different inlet conditions but may not achieve the full benefits of BLI. This paper presents a technique for cycle analysis which can account for the disparity between inlet conditions. This technique was used for two principal purposes: first to determine the effect of the inlet disparity on the performance of the system; second, to analyze the various design strategies that might mitigate the impact of this effect. It is shown that a single engine can be sized when considering both inboard and outboard engines simultaneously. Additionally, it is shown that there is a benefit to ingesting larger mass flows in the inboard engine for the case with large disparity between the engine inlets.

scholarly journals Noise Response of P53 Oscillation against System Size Scaling

2015 ◽  
Vol 108 (2) ◽  
pp. 150a
Author(s):  
Chong He Yue ◽  
Lock Chew
Keyword(s):  
System Size ◽  
Size Scaling

scholarly journals Dissecting the effects of nitrate, sucrose and osmotic potential on Arabidopsis root and shoot system growth in laboratory assays

2012 ◽  
Vol 367 (1595) ◽  
pp. 1489-1500 ◽  
Author(s):  
Peter Roycewicz ◽  
Jocelyn E. Malamy
Keyword(s):  
Root System ◽  
Osmotic Potential ◽  
Wide Spectrum ◽  
System Size ◽  
Growth Media ◽  
Target Tissue ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Shoot System ◽  
The Impact

Studying the specific effects of water and nutrients on plant development is difficult because changes in a single component can often trigger multiple response pathways. Such confounding issues are prevalent in commonly used laboratory assays. For example, increasing the nitrate concentration in growth media alters both nitrate availability and osmotic potential. In addition, it was recently shown that a change in the osmotic potential of media alters the plant's ability to take up other nutrients such as sucrose. It can also be difficult to identify the initial target tissue of a particular environmental cue because there are correlated changes in development of many organs. These growth changes may be coordinately regulated, or changes in development of one organ may trigger changes in development of another organ as a secondary effect. All these complexities make analyses of plant responses to environmental factors difficult to interpret. Here, we review the literature on the effects of nitrate, sucrose and water availability on root system growth and discuss the mechanisms underlying these effects. We then present experiments that examine the impact of nitrate, sucrose and water on root and shoot system growth in culture using an approach that holds all variables constant except the one under analysis. We found that while all three factors also alter root system size, changes in sucrose and osmotic potential also altered shoot system size. In contrast, we found that, when osmotic effects are controlled, nitrate specifically inhibits root system growth while having no effect on shoot system growth. This effectively decreases the root : shoot ratio. Alterations in root : shoot ratio have been widely observed in response to nitrogen starvation, where root growth is selectively increased, but the present results suggest that alterations in this ratio can be triggered across a wide spectrum of nitrate concentrations.

Employing Multidimensional Data Visualization Tools to Assess the Impact of Constraint Uncertainties on Complex Design Problems

2017 ◽  
Author(s):  
Gary M. Stump ◽  
Simon W. Miller ◽  
Michael A. Yukish ◽  
Christopher M. Farrell
Keyword(s):  
Data Visualization ◽  
Decision Makers ◽  
Multidimensional Data ◽  
Design Problems ◽  
Design Constraints ◽  
Performance Space ◽  
Multidimensional Data Visualization ◽  
Complex Design ◽  
Visualization Tools ◽  
The Impact

A potential source of uncertainty within multi-objective design problems can be the exact value of the underlying design constraints. This uncertainty will affect the resulting performance of the selected system commensurate with the level of risk that decision-makers are willing to accept. This research focuses on developing visualization tools that allow decision-makers to specify uncertainty distributions on design constraints and to visualize their effects in the performance space using multidimensional data visualization methods to solve problems with high orders of computational complexity. These visual tools will be demonstrated using an example portfolio design scenario in which the goal of the design problem is to maximize the performance of a portfolio with an uncertain budget constraint.

Reduction of Power Losses in Bearing Chambers Using Porous Screens Surrounding a Ball Bearing

2005 ◽  
Vol 128 (1) ◽  
pp. 178-182 ◽  
Author(s):  
Michael Flouros
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Research Programme ◽  
Aircraft Engine ◽  
Chamber Pressure ◽  
Power Losses ◽  
Torque Measurements ◽  
Engine Design ◽  
Oil Flow ◽  
The Impact

Trends in aircraft engine design have caused an increase in mechanical stress requirements for rolling bearings. Consequently, a high amount of heat is rejected, which results in high oil scavenge temperatures. An RB199 turbofan bearing and its associated chamber were modified to carry out a survey aiming to reduce power losses in bearing chambers. The test bearing was a 124 mm PCD ball bearing with a split inner ring employing under-race lubrication by two individual jets. The survey was carried out in two parts. In the first part, the investigations were focused on the impact on the power losses in the bearing chamber of the operating parameters, such as oil flow, oil temperature, sealing air flow, bearing chamber pressure, and shaft speed. In the second part, the investigations focused on the reduction of the dwell time of the air and oil mixture in the bearing compartment and its impact on the power losses. In this part, porous screens were introduced around the bearing. These screens would aid the oil to flow out of the compartment and reduce droplet-droplet interactions as well as droplet-bearing chamber wall interactions. The performance of the screens was evaluated by torque measurements. A high-speed camera was used to visualize the flow in the chamber. Considerable reduction in power loss was achieved. This work is part of the European Research programme GROWTH ATOS (Advanced Transmission and Oil Systems).

scholarly journals Role of weakest links and system-size scaling in multiscale modeling of stochastic plasticity

2017 ◽  
Vol 95 (5) ◽  
Author(s):  
Péter Dusán Ispánovity ◽  
Dániel Tüzes ◽  
Péter Szabó ◽  
Michael Zaiser ◽  
István Groma
Keyword(s):  
Multiscale Modeling ◽  
System Size ◽  
Size Scaling

Trial of New Concept Diesel Combustion System - Premixed Compression-Ignited Combustion -

1999 ◽  
Author(s):  
Yoshinori Iwabuchi ◽  
Kenji Kawai ◽  
Takeshi Shoji ◽  
Yoshinaka Takeda
Keyword(s):  
Diesel Combustion ◽  
Combustion System

System Approach for Compliance with Full Load Targets on a Wall Guided Diesel Combustion System

2008 ◽  
Vol 1 (1) ◽  
pp. 501-513 ◽  
Author(s):  
V. Cursente ◽  
P. Pacaud ◽  
S. Mendez ◽  
V. Knop ◽  
L. de Francqueville
Keyword(s):  
System Approach ◽  
Diesel Combustion ◽  
Combustion System ◽  
Full Load

scholarly journals THE IMPACT OF MOTORIZED VEHICLE ACTIVITY ON THE LEVEL OF AIR POLLUTION IN BALI ISLAND

2020 ◽  
Vol 8 (4) ◽  
pp. 256-261
Author(s):  
Dinda One Mulyaningtyas ◽  
I Ketut Widnyana ◽  
Sang Putu Kaler Surata
Keyword(s):  
Air Pollution ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Combustion System ◽  
High Carbon ◽  
Engine Combustion ◽  
Vehicle Activity ◽  
Motorized Vehicles ◽  
The Impact ◽  
The City

Number of vehicles moving in the city of Denpasar is quite dense and has the potential to produce high carbon monoxide (CO) and hydrocarbon (HC) exhaust gases which can be fatal to human health. The research objective is to analyze the level of air pollution in the city of Denpasar and analyze the factors that cause pollution from motorized vehicles. To calculate the volume of traffic using the application traffic counter on an android phone. The research method uses trend analysis and multiple linear regression analysis. The growth of CO pollutants in the city of Denpasar increased with a growth value of 0.88 to 3.25 per year so that in 2021 the level of CO is predicted to be between 32.41% to 81.52%. Likewise, HC levels increase with a growth value of 0.85 - 1.59 per year so that in 2021 HC levels are predicted between 2,670 ppm to 24,383 ppm. The vehicles age and engine combustion system have a strong correlation in producing CO and HC values; while brand, engine capacity and mileage correlate very weak. The conclusion is that newer vehicles and the latest combustion systems produce lower CO and HC levels.

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